This invention relates generally to an electronic reprographic printing system, and more particularly concerns feeder apparatus process for improving feeding of compilations of recording sheets that often accompanies this general method of reproduction and printing.
Cross reference is made to the following applications filed concurrently herewith: U.S. patent application Ser. No. 09/591,820 entitled xe2x80x9cA Sheet Feeding Apparatus Having An Air Plenum With A Corrugated Surfacexe2x80x9d, U.S. patent application Ser. No. 09/591,822 entitled xe2x80x9cA Sheet Feeding Apparatus Having An Air Plenum With A Sealxe2x80x9d, U.S. patent application Ser. No. 09/591,909 entitled xe2x80x9cA Sheet Feeding Apparatus Having An Air Plenum With A Leaky Sealxe2x80x9d, and U.S. Pat. No. 6,264,188 entitled xe2x80x9cA Sheet Feeding Apparatus Having An Adaptive Air Flufferxe2x80x9d.
In the process of electrostatographic reproduction, a light image of an original to be copied or printed is typically recorded in the form of a latent electrostatic image upon a photosensitive member, with a subsequent rendering of the latent image visible by the application of electroscopic marking particles, commonly referred to as toner. The visual toner image can be either fixed directly upon the photosensitive member or transferred from the member to another support medium, such as a sheet of plain paper. To render this toner image permanent, the image must be xe2x80x9cfixedxe2x80x9d or xe2x80x9cfusedxe2x80x9d to the paper, generally by the application of heat and pressure.
With the advent of high speed xerography reproduction machines wherein copiers or printers can produced at a rate in excess of three thousand copies per hour, the need for sheet handling system to, for example, feed paper or other media through each process station in a rapid succession in a reliable and dependable manner in order to utilize the full capabilities of the reproduction machine. These sheet handling systems must operate flawlessly to virtually eliminate risk of damaging the recording sheets and generate minimum machine shutdowns due to misfeeds or multifeeds. It is in the initial separation of the individual sheets from the media stack where the greatest number of problems occur which, in some cases, can be due to up curl and downcurl in sheets which generally occur randomly in the document stack.
There is provided a sheet feeding apparatus for feeding a compilation of sheets in a process direction to a process station, comprising: a sheet tray for holding said compilation of sheets; an air plenum, positioned above said compilation of sheets, said plenum including a corrugated surface having a first set of ribs at a first height and a second set of ribs at a second height; and a blower for generating a vacuum force in said air plenum to drive one of said compilation of sheets into contact with said corrugated surface.
An object of the present invention is a sheet feeder apparatus. In this apparatus, air is used to help sheet separation, fluff sheet up, acquire sheet from the media tray and remove extra sheets away from the sheet being fed.